Well, that entirely depends upon the sort of people you want to meet. If you're not very picky, then you'll find a lot of places at bars and clubs. There's always loads of people at those places.
If that's now your crowd and if you're in school, try clubs. I found most of my friends through clubs, and then more friends through those friends. And the benefit of that is you already know you have at least one thing in common. When I went to anime club, I knew I was going to meet people who liked anime.
I don't think I can really give you much advice for meeting people outside of college, I've never been in that situation. Search for community clubs, maybe? Volunteer somewhere? And once again there's always bars.